The present invention relates to a novel dwarfism allele of cleome, which results in a reduction in plant size. This present invention also relates to a cleome seed, a cleome plant, a cleome variety and a cleome hybrid, which contain the dwarfism allele. In addition, the present invention is directed to transferring the dwarfism allele in the cleome plant to other cleome varieties and species and is useful for producing novel types and varieties of dwarf cleome.
Cleome of the family Capparidaceae, is composed of approximately 200 species of annual or perennial herbs and sub shrubs. One annual species, Cleome hasslerana, has been cultivated as a garden and border plant. Only a few varieties of cleome are available commercially, including xe2x80x98Helen Campbellxe2x80x99, xe2x80x98White Queenxe2x80x99, xe2x80x98Pink Queenxe2x80x99, xe2x80x98Rose Queenxe2x80x99, xe2x80x98Cherry Queenxe2x80x99 and xe2x80x98Violet Queenxe2x80x99. With the exception of flower color, these varieties are very similar in appearance and performance, growing as frost-tender annuals to a height of approximately five feet. To date, no other plant form of Cleome hasslerana has been available and there is no known dwarfism in any cultivars of Cleome. A dwarf form of cleome would be particularly desirable to the commercial greenhouse trade as well as to commercial landscape and home gardeners.
The present invention relates to a cleome seed, a cleome plant, a cleome variety, a cleome hybrid, and a method for producing a cleome plant.
More specifically, the invention relates to a dwarfism allele, which produces a cleome plant that is reduced in size.
In one aspect of the invention, under greenhouse production, the dwarf cleome of the present invention can be grown in a smaller container and under a higher bench density than the standard form. In another aspect the dwarf cleome of the present invention can be shipped in flower at a much reduced height and size, allowing higher shipping density and reduced cost per unit. Shipping and sale in flower increases unit value. In another aspect of this invention the dwarf cleome translates into higher display density and greater visual appeal, increasing per unit value for the retailer. The consumer is offered a novel and more appealing product at the point of sale, which is more easily transported and has a wider utility in the home landscape. In the garden, the dwarf form of the present invention, with it""s compact growth habit and compressed flower canopy, offers a plant with a broader range of uses and greater color impact.
The genetic factor of the present invention which is capable of transmitting the plant size reduction has been determined to be a mutant single recessive allele, which has been designated xe2x80x9cH35xe2x80x9d. It is a feature of the present invention that this single mutant allele H35 may be used in and transferred to different cleome varieties and to other cleome species.
The present invention further relates to a method of producing the disclosed cleome plants and seeds by crossing a dwarf cleome plant of the instant invention with another cleome plant. The invention also relates to the transfer of the genetic dwarfism into other cleome plants.
In order to provide an understanding of the terms used in the specification and claims, the following definitions are provided:
Dwarf, dwarfismxe2x80x94means a plant possessing shortened internodes and reduced foliage size, resulting in a smaller than normal plant form.
Compact growth habitxe2x80x94means plants that are smaller than normal as a result of shortened internodes.
Maturexe2x80x94means 5-month-old field grown plants derived from transplanted plantlets. The plantlets are grown from seed in the greenhouse for approximately 6 weeks prior to being transplanted.
Mature plant heightxe2x80x94means the measurement in inches from the soil line to the uppermost tip of the plant. Mature plant height data was taken on 5-month-old field grown plants.
Mature plant widthxe2x80x94means the measurement in inches at the broadest point of the plant. Data was taken on 5-month-old field grown plants.
Leaf lengthxe2x80x94means the distance in inches between the base of the petiole and the tip of the primary leaflet. Leaf samples were taken from two nodes below the first flower on 5-month-old field grown plants.
Leaf width indexxe2x80x94means the sum of the length in inches of the two leaflets adjacent to the primary leaflet. Leaf samples were taken from two nodes below the first flower on 5-month-old field grown plants.
Plant height at first flowerxe2x80x94means the total height of the plant in inches from the soil line to the first fully opened flower. Data was taken on field grown plants.
Field conditionsxe2x80x94means plants grown to maturity in an open field. Seeds are sown in the greenhouse and grown for approximately 6 weeks to produce plantlets. These plantlets are then transplanted to the field on or about the average last day of frost for the specific field location.
The present invention relates to a novel plant-dwarfing allele in the genus Cleome that is phenotypically expressed in the reduction in plant size. As the term is used herein, dwarf and dwarfism refer to a condition where in the plant and all its parts are reduced in size by a substantial amount. Additionally, the plant parts, being smaller, have a finer texture and a more delicate appearance than those of standard cleome.
This present invention is directed to developing unique plants of the cleome species. The cleome of the present invention expresses a substantial reduction in plant size. A transferable gene or allele that conveys this dwarf characteristic has been isolated and incorporated into other genetic backgrounds. The dwarf allele of the instant invention has also been expressed in different genetic backgrounds of cleome. The present invention results in a mature plant height reduction of about 30% to about 50%, plant width reduction of about 20% to about 40%, and reduction of plant height at first flower of about 40% to about 60%, depending on the genetic background as shown in Tables 1-3. To date, except for the present invention, there is no known dwarfism in any cultivars of Cleome.
It is standard practice in the industry to treat young plants several times with chemical plant growth regulators (PGR) such as B-9 (Alar), Cycocel or Bonzi to reduce internode length to obtain shorter, more compact plants. While this effect may appear somewhat similar to that of the dwarfing allele, it is important to note that this effect is temporary and the plants will achieve their full height potential when planted out in the field and grown full season. Genetic dwarf lines will also develop proportionately shorter and more compact plants following treatment with PGRs, resulting in plants even smaller than the same PGR-treated commercial varieties.
As used herein, the term plant includes plant cells, plant protoplasts, plant cell tissue cultures from which cleome plants can be regenerated, plant calli, plant clumps and plant cells that are intact in plants or parts of plants, such as embryos, pollen, ovules, flowers, stems, leaves, roots, root tips, anthers, and the like.